The mouse colony, genotyping and antibody core (MCGAC) will I. Breed and genotype the genetically engineered mice generated for and during the program project period. The core will generate crosses and backcrosses to obtain mice in the desired genetic background. II. Generate monoclonal antibodies to NWASP, WASP and to any other proteins requested by the investigators. The cost of animal housing is becoming very expensive; therefore it is impossible for individual investigator to maintain colonies of all the genetically engineered mice necessary for the program project. MCGAC will centralize the maintenance of breeder colony and coordinate breeding of experimental animals in parallel for more than one investigator. Working as a group should result in minimal animal wastage and cost savings. Because of the location of Dr. Snapper's laboratory at MGH, he will maintain his own mouse colony. This is reflected in the budgets of Project #2, which includes mouse costs. Nevertheless, every effort will be made to save costs by sharing tissues among all 4 investigators whenever possible. The second aim of the MCGAC is to generate, characterize and standardize the mAbs against the proteins being investigated in the program project. Many of the proteins investigated in the program project are novel and the investigators have to depend on the few commercial antibodies or antisera that are available against these proteins. Purchase of antibodies adds a significant expense to the Program project investigators. MCGAC will generate virtually inexhaustible supply of several monoclonal antibodies that will not only benefit the investigators of the Program Project but also the WASP research community at large.